Round filter element, in particular for gas filtration

ABSTRACT

A round filter element has a filter medium body with a wall to be flowed through by a fluid to be purified in a radial direction relative to a longitudinal axis of the filter medium body. A circumferentially extending seal carrier is arranged at or adjacent to an end face of the filter medium body. A sealing element is supported at the seal carrier adjacent to a radial outer side of the filter medium body. A positioning element extends into the filter medium body and engages with form fit a correlated housing-associated counter positioning element of a filter housing when the round filter element is installed in the filter housing. The seal carrier separates flow-tightly a raw side of the round filter element from a clean side of the round filter element when the round filter element is installed in the filter housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of internationalapplication No. PCT/EP2017/076233 having an international filing date of13 Oct. 2017 and designating the United States, the internationalapplication claiming a priority date of 17 Oct. 2016 based on priorfiled German patent application No. 102016012327.3, the entire contentsof the aforesaid international application and the aforesaid Germanpatent application being incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention concerns a round filter element, in particular for gasfiltration, for example, for an air filter, with a filter medium bodywhose wall can be flowed through by the fluid to be purified relative tothe longitudinal axis of the filter medium body in radial direction,with at least one end disk at an end face of the filter medium body.

US 2013/0 232934 A1 discloses a round filter element that can be used inan air filter, for example, in the intake manifold of an internalcombustion engine. The filter element is provided with a hollowcylindrical filter medium body having a support grid for supporting thefilter medium body arranged at its outer side. The outwardly positionedwall surface of the filter medium body is provided with a V-shaped cutinto which a rod-shaped positioning element is inserted which, in theinstalled state inside the receiving filter housing, prevents accidentalrotation about the longitudinal axis of the filter element. The walls inthe region of the V-shaped cut of the filter medium body are sealedflow-tightly. For sealing the raw side relative to the clean side of thefilter element, a circumferentially extending sealing element isprovided in the region of an end disk at an end face of the filtermedium body.

SUMMARY OF THE INVENTION

It is the object of the invention to embody with simple constructivemeasures a round filter element in such a way that the round filterelement is reliably received in the filter housing in the installedstate.

This object is solved according to the invention in that at or adjacentto an end face of the filter medium body a circumferentially extendingseal carrier is arranged on which a sealing element is supportedadjacent to the outer side of the filter medium body and in that, at theround filter element, a positioning element extending into the filtermedium body is arranged for form-fit connection of the round filterelement with a correlated housing-associated counter positioning elementin the installed state in the filter housing, wherein the seal carrierseparates flow-tightly the raw side from the clean side.

The dependent claims provide expedient further embodiments.

The round filter element according to the invention is preferably usedfor gas filtration, for example, for filtration of air, in particular inthe intake manifold of an internal combustion engine of a vehicle. Thefilter element comprises a filter medium body whose wall is flowedthrough by the fluid to be purified. The filter medium body surrounds aninwardly positioned flow space that is delimited by the inner wall ofthe filter medium body. Relative to its longitudinal axis, the filtermedium body is flowed through in radial direction, preferably radiallyfrom the interior to the exterior, so that the inwardly positioned flowspace adjoins the raw side of the filter medium body and the outer sideof the filter medium body forms the clean side via which the purifiedfluid exits. At least at one axial end face, preferably at bothoppositely positioned axial end faces, the filter medium body is coveredflow-tightly by end disks.

In a preferred embodiment, an end disk comprises a central opening,communicating with the inwardly positioned flow space, for axial flowconveyance of the fluid; however, the oppositely positioned end disk isembodied to be closed and closes off the inwardly positioned flow spaceoutwardly in axial direction.

Expediently, the end disk of the filter element that is provided withthe central opening is rounded at its radial inner side whereby theinflow of the raw air into the interior in the filter medium body isfacilitated. This is of particular importance in connection with theinflow into the interior of the filter element for minimizing the totalpressure loss when, as preferred in the present case, the air flowsfreely into the interior and, as further preferred in the present case,no flow pipe is provided that guides the air flow directly into theinterior. The radius of the rounded portion at the radial inner side ofthe end disk is advantageously larger than at the radial outer side. Theradius at the radial inner side is embodied, as needed, so large thatthe starting point of the radius at the end face is still within thecontour of the filter medium body. The radius of the rounded portion atthe radial inner side of the end disk lies, for example, in a rangebetween 5 mm and 15 mm, for example, is 7.5 mm.

The round filter element with the filter medium body can be embodied tobe hollow cylindrical or not rotation-symmetric, for example, can havean oval or ovalized cross section shape, wherein also cross sectionshapes with parallel long sides and semicircular narrow sides areconceivable and the long sides can be curved slightly convexly orconcavely externally or inwardly. In a preferred embodiment, the innerwall and the outer wall of the filter medium body extend concentricallyto each other so that the filter medium body has a constant radialthickness, even though also embodiments are possible however in whichthe filter medium body has a changing radial thickness along itscircumference.

According to a further expedient embodiment, the round filter elementhas a cross section shape that tapers in axial direction so that theouter circumference of the round filter element in the region of thefirst end disk is of a different size in comparison to the outercircumference of the round filter element in the region of theoppositely positioned second end disk. In this embodiment, round crosssection shapes in the region of both end discs are also conceivable sothat the round filter element and the filter medium body are embodied ina conical shape. Moreover, it is possible to provide an oval or ovalizedcross section shape, respectively, in the region of both end disks.

In case of a tapering cross section shape of the round filter element,the end disk at the end face with the smaller outer circumference can beembodied to be closed and can close off axially the inwardly positionedflow space, while the oppositely positioned end disk at the larger outercircumference comprises a flow opening for introducing fluid into theinwardly positioned flow space.

Moreover, embodiments are also possible in which the end disk at the endface with the larger outer circumference is embodied to be closed andcloses off axially the inwardly positioned flow space, and theoppositely positioned end disk at the smaller outer circumferencecomprises a flow opening for introducing fluid into the inwardlypositioned flow space.

The round filter element according to the invention comprises at theouter wall of the filter medium body a support grid that is inparticular embodied to be shape-stable. The support grid is, forexample, embodied as a thermoplastic injection-molded part. Due to theflow through the filter medium body in radial direction from theinterior to the exterior, the wall of the filter medium body issubjected to a radial outwardly oriented pressure under which the wallhas the tendency to curve outwardly. The support grid at the outer wallof the filter medium body prevents a deformation of the wall outwardlyin radial direction and thus maintains the shape of the filter mediumbody during filtration so that a deformation is avoided.Correspondingly, the filter medium body maintains over a long operatingperiod its original geometric shape, and the flow conditions duringfiltration of the fluid are maintained. Also, the filter medium bodyexperiences at the outer side a support action by the support grid sothat the filter medium body is subjected to reduced loads and the riskof damage of the filter medium body is reduced. Advantageously, at leastone end face of the support grid, as needed, both end faces, areembedded in the end disks. At least one end disk is comprised preferablyof a softer material than the support grid and a seal carrier at thefilter element which receives a sealing element. Preferably, the enddisk or the end disks are produced of a pourable material such as, as anexample and preferred, polyurethane (PUR), in particular polyurethanefoam.

The filter medium body is preferably configured as a folded filter witha plurality of filter folds. The filter folds extend preferably in orapproximately in radial direction and thus in the flow direction andextend at the same time axially between the two end faces of the filtermedium body. The folded filter is of an annularly closed configuration.

In particular, precisely one filter medium body embodied as a roundfilter is arranged in the filter element or encompassed by the filterelement.

According to a further advantageous embodiment, a shaped body projectsinto one end face of the filter medium body and stabilizes additionallythe filter medium body and secures the filter folds in the desiredposition in the embodiment as a folded filter. In the embodiment with atapering cross section surface, the shaped body is preferably located atthe end face with reduced cross section surface. The shaped body can beembodied as one piece together with the support grid at the filtermedium body so that supporting forces, acting on the end face of thefilter element with the shaped body, are distributed through the shapedbody to the support grid and the end disk is relieved from thesupporting forces.

The outer contour of the shaped body corresponds advantageously to theouter contour and/or the inner contour of the filter medium body at itsend face into which the shaped body is projecting into the filter mediumbody. It can be expedient to connect the shaped body at least oversections thereof to the neighboring end disk, for example, to form asupport sleeve on the shaped body that is projecting into the end disk.The end disk into which one or a plurality of sections of the shapedbody are projecting is preferably of a closed configuration and sealsflow-tightly the interior inside the filter medium body. As needed, theshaped body can taper within the space surrounded by the filter mediumbody toward its free end face in particular in a wedge shape whereby themanufacturing process of the filter element is simplified and supported.The shaped body is in particular embodied as an elongate body andextends along the long sides of the filter element between oppositesides of the support grid, in particular the short sides with pronouncedcurvature. When producing the filter element, the filter medium body iscentered and is brought into the shape which the filter medium body isto assume in final position by means of the shaped body when pushing thefilter medium body onto the shaped body.

According to an advantageous embodiment, the round filter elementcomprises a sealing element, in particular a circumferentially extendingsealing ring, that is arranged at a seal carrier, embodied in particularseparate from the end disk, and arranged adjacent to the end disk,arranged at the raw air side and/or open, through which the unpurifiedfluid can be introduced into the inwardly positioned flow space. In thiscontext, the sealing element is positioned axially and radially at aspacing relative to the neighboring nearest end disk. In particularviewed in the direction of the longitudinal axis of the filter element,it is arranged between the two end faces of the filter medium body andbetween the two end disks and spaced apart relative to them. In otherwords, the sealing element defines a sealing plane which is locatedbetween and preferably parallel to the end faces of the filter mediumbody or the end disks. By means of the sealing element, a flow-tightseparation of the raw side from the clean side is realized. Due to theconfiguration of the sealing carrier separate from the end disk, the enddisk is not subjected to the holding and sealing forces which areabsorbed by the sealing element and the seal carrier in the installationsituation of the round filter element. The end disk therefore remainsunaffected by the holding and sealing forces. Due to the spacing of thesealing element and advantageously also of the seal carrier axially andradially relative to the neighboring end disk, seal carrier and sealingelement also have a spacing relative to the clean side or outer side ofthe filter medium body so that the fluid can exit through the clean sideof the filter medium, unhindered by the seal carrier and by the sealingelement. The seal carrier is fluid-tightly embodied and connectsadvantageously the nearest end disk fluid-tightly with the sealingelement, i.e., the end disk arranged at the raw air side and/or open andneighboring the seal carrier.

The seal carrier is axially spaced apart relative to the end face of theneighboring nearest end disk. Relative to the total axial height of thefilter element, the axial spacing amounts to, for example, maximally 30%of the axial height, preferably maximally 20% of the axial height, ormaximally 10% of the axial height.

According to a preferred embodiment, the seal carrier is arranged at thesupport grid. In particular, a one-piece configuration of support gridand seal carrier is conceivable, which are preferably embodied asplastic components. The sealing and holding as well as supporting forcesare absorbed correspondingly by the seal carrier and the support gridwhile the filter medium body is relieved of these forces.

According to a further advantageous embodiment, the seal carrier isembodied as a circumferentially extending carrier wall or comprises acircumferentially extending carrier wall which is extending at a spacingrelative to the outwardly positioned wall surface of the filter mediumbody. The carrier wall extends in particular parallel to the outwardlypositioned wall surface of the filter medium body. In this way, thecarrier wall can preferably form a tube section surrounding the filtermedium body about a portion of its length having the sealing elementarranged at its one end or end face and, at its other end or end face,the carrier wall is preferably, and in particular seal-tightly,connected with the neighboring end disk or end disk nearest the sealingelement. The sealing element is advantageously inserted into a receivinggroove in the carrier wall, wherein the receiving groove is preferablylocated at or adjacent to an end face of the carrier wall. The positionof the sealing element at the carrier wall is located at the end surfaceor end face of the carrier wall which is facing away from the nearestend disk.

In a preferred embodiment, the seal carrier or the carrier wall, inparticular at the end face of the seal carrier or carrier wall facingaway from the sealing element, is connected seal-tightly and preferablywith form fit to the end disk nearest the sealing element, i.e., theopen end disk, in particular is embedded therein or glued thereto. Incases in which seal carrier and support grid are formed as one piece,the unit of seal carrier and support grid can advantageously beconnected respectively in such a way to both end disks, preferablyrespectively by embedding the respective end face ends in the respectiveend disk, so that the end face ends of seal carrier and support grid areembedded with form fit in the end disks.

The seal carrier is supported advantageously in the installed positionat a housing component, for example, at an inwardly positioned shoulderin a filter housing base that receives the filter element and to which ahousing cover can be attached.

At the end face, in particular at the top side of the seal carrier,knobs can be integrally formed, as needed, advantageously with axialspacing relative to the end face. These knobs have the function of atolerance compensation and can compensate deviations of the seal carrierrelative to a plane surface for attaching the housing cover and/orplacing onto the shoulder in the filter housing base. The knobs are, forexample, rod-shaped and are positioned parallel to the sidewall of theseal carrier; the rod-shaped knobs extend, for example, in radialdirection. In the installed position, the knobs are pressed into thematerial of the housing component and/or the knobs are in particularelastically or plastically deformed and compensate thereby tolerancedeviations. Preferably, a softer material is selected for the knobs thanfor the housing component (in particular the housing cover) so that thedeformation is substantially or completely realized by the knobs.

According to a further embodiment that relates in particular to a roundfilter element with a cross section shape that tapers in axialdirection, the smaller end disk comprises radially projecting supportcams. Advantageously, these support cams project in radial direction nofarther than the oppositely positioned end disk or the inner contour orouter contour of the oppositely positioned seal. However, a slightprotrusion may be provided in order to achieve a particularly strongclamping action. The inner contour of seal carrier and/or sealingelement extend advantageously in radial direction substantially alongthe outer circumference of the larger end disk.

In case of an oval or ovalized cross section shape of the filter mediumbody, the support cams are preferably located at the long sides and arein particular arranged at the end disk, preferably at the smaller enddisk, in particular embodied as one piece together with the end disk andintegrally formed thereat. However, it is also possible to arrangeadditionally at the narrow side one or several cams at the end disk. Thecams project in radial direction past the end disk and supportpreferably the round filter element in the installed state at thereceiving filter housing.

A further aspect of the invention relates to a filter device with anafore described round filter element and with a filter housing forreceiving the round filter element.

The filter housing includes in particular also a housing cover which canbe attached to a filter housing base in order to close off the receivingspace inside the filter housing base in which the filter element isinserted. At the inner side of the housing cover, according to a furtheradvantageous embodiment, a preferably blade-shaped flow guiding rib isarranged which assists in introducing the fluid flow into the inwardlypositioned flow space and in uniform particle loading of the filterelement during the filtration of the fluid, in particular also in caseof non-symmetrical or non-parallel flow conditions. The unpurified fluidis preferably guided from the exterior radially in the direction towardthe filter medium body and impinges then on the flow guiding rib at theinner side of the housing cover which influences the impacting fluidflow, for example, divides it into two and/or deflects it in axialdirection toward the inwardly positioned flow space inside the filtermedium body.

Different embodiments of the flow guiding rib are conceivable. The flowguiding rib is embodied either to be straight and positioned in a planeor, according to an alternative embodiment, curved. In case of astraight configuration, the flow guiding rib can extend in axialdirection of the filter element so that the wall faces of the flowguiding rib extend parallel to the longitudinal axis of the filterelement.

The flow guiding rib can protrude into the flow opening which isprovided in the end disk of the round filter element through which theunpurified fluid is introduced into the inwardly positioned flow spaceinside the filter medium body.

According to a further expedient embodiment, a lateral inflow openingthrough which the unpurified fluid flows in radially is provided in thehousing cover and is pointing in radial direction. The flow guiding ribcan be arranged adjacent to this inflow opening in the housing cover.The flow guiding rib can be positioned in such a way that the end faceof the flow guiding rib is facing the inflow opening in the housingcover. The fluid flow which is radially supplied through the housingcover impacts on the flow guiding rib and experiences a deflection inthe direction toward the inwardly positioned flow space inside thefilter medium body. The flow guiding rib and the inflow opening can beoriented at least approximately parallel.

Advantageously, a lateral inflow opening is also provided in the filterhousing base of the filter housing for the fluid to be supplied whereinthis inflow opening in the filter housing base and the lateral inflowopening in the housing cover in the mounted state lie on top of eachother and form a continuous flow path for the supplied fluid.

According to a further expedient embodiment, a lateral outflow openingis provided in the filter housing base, which is oriented preferably inradial direction and through which the purified fluid flows out. It canbe expedient that the outflow opening is oriented at least approximatelyparallel to the inflow opening as well as to the flow guiding rib.

According to a further expedient embodiment, the filter element in theinstalled state is projecting axially slightly past the end face of thefilter housing base whereby the removal of the filter element from thefilter housing base, for example, for servicing purposes, isfacilitated. The seal carrier with the sealing element is positioned ata small axial spacing relative to the projecting end face of the filterelement and provides for a flow-tight separation between the outwardlypositioned section of the filter element and the inwardly positionedsection of the filter element received in the filter housing base.

At or adjacent to an end face, a circumferentially extending sealcarrier is arranged at the round filter element where, in the installedstate inside the filter housing, a sealing element is supported which ispositioned adjacent to the radial outer side of the filter medium body.The sealing element is advantageously arranged at the seal carrier ofthe round filter element, in particular inserted in a receiving groovein the sealing carrier wherein also embodiments are conceivable in whichthe sealing element is located in the filter housing and the sealingelement is resting against the seal carrier of the round filter elementonly in the installed state. In the installed state, the sealing elementseparates the raw side from the clean side of the filter element.

At the filter element a positioning element is arranged with which aform-fit connection of the round filter element with a correlatedhousing-associated counter positioning element can be produced in theinstalled state.

Advantageously, the seal carrier is also carrier of the positioningelement. The form-fit connection between positioning element at theround filter element and counter positioning element at the filterhousing relates to at least one relative movement possibility of theround filter element relative to the filter housing and serves, forexample, as an anti-rotation device of the round filter element in thefilter housing or as a positioning aid for the filter element and/or ahousing part when exchanging the round filter element in the housing ina service situation. By means of the positioning element and thecorrelated housing-associated counter positioning element, the positionof the round filter element in the filter housing is unequivocallydetermined whereby the insertion of the filter element into the filterhousing is simplified. This is achieved in a constructively simpleembodiment in that the positioning element is arranged at the filterelement, in particular in that the seal carrier, in addition toabsorbing the sealing forces which are caused by the sealing element, isalso carrier of the positioning element.

The seal carrier flow-tightly separates the raw side and the clean sidefrom each other at the filter element so that a flow bypass of the fluidto be purified by bypassing the filter medium body is precluded.

The seal carrier is advantageously of an annular configuration and ispositioned in a plane that is oriented orthogonally to the longitudinalaxis of the filter element. Sealing element and positioning element canbe positioned, for example, at oppositely positioned axial side faces ofthe seal carrier.

The circumferentially extending seal carrier also provides for higherstability of the round filter element, in particular in radialdirection. The outer rim of the seal carrier can optionally be supportedat the inner wall of the receiving filter housing.

In case of an annular embodiment of the seal carrier, the latter isadvantageously positioned at the in particular radial outer side of thefilter medium body. The sealing element is also located at the radialouter side of the filter medium body. The filter medium body isadvantageously flowed through radially from the interior to the exterioror from the exterior to the interior by the fluid to be purified so thatthe seal carrier and the sealing element are located at the clean sideof the filter medium body.

According to an advantageous embodiment, the positioning element isformed as one piece together with the seal carrier. The seal carrier ispreferably embodied as a plastic component that is producible inparticular by an injection molding process. As needed, also a two-partconfiguration of positioning element and seal carrier is conceivablewherein, in this case, the positioning element is advantageously fixedlyconnected to the seal carrier or to a support grid at the filter mediumbody.

According to a further advantageous embodiment, the positioning elementextends optionally into the filter medium body, in particular radiallyinto the filter medium body. Advantageously, the annular seal carriersurrounds the filter medium body and the positioning element is locatedat the radial inwardly positioned side of the seal carrier and ispositioned thus at least with sections thereof within the filter mediumbody. This embodiment has the advantage that an additional, radiallyoutwardly projecting space is not required for the arrangement of thepositioning element. Accordingly, the maximum radial extension of thefilter element is determined by the outwardly positioned rim area of theseal carrier.

According to a further expedient embodiment, the positioning element isin particular embodied as a wedge-shaped hollow body into which thehousing-associated counter positioning element projects in the mountedstate. The hollow body receives the, for example, blade-shaped counterpositioning element so that a form-fit connection between positioningelement and counter positioning element is achieved, wherein the formfit is effective as needed in all radial directions. In case ofcorrectly installed position of the filter element inside the filterhousing, advantageously no or only a slight contact without forcetransmission exists between positioning element and counter positioningelement.

In an alternative embodiment, the counter positioning element isembodied as a hollow body into which the positioning element projects.

According to a further advantageous embodiment, relating to thepositioning element as a hollow body, a bottom in the form of a bottomplate is provided in the hollow space within the positioning element forflow-tight sealing of the hollow space. In this way, it is ensured thatan undesired bypass between raw side and clean side through thepositioning element embodied as a hollow body is prevented. As analternative to a bottom, also a conical tapering of the walls of thehollow body is conceivable that meet at the pointed side of the hollowbody and close it off flow-tightly in axial direction.

According to a further expedient embodiment, the bottom in the hollowspace of the positioning element is located axially at the level of theseal carrier. The seal carrier is thus extended radially into thepositioning element in order to from the bottom in the hollow space ofthe positioning element which, at the same time, represents an axialboundary for the counter positioning element which is axially insertedinto the hollow space.

According to a further expedient embodiment, the positioning element isembodied as an elongate body, for example, as a wedge, whoselongitudinal axis extends in radial direction, and is arranged inparticular at the radial inner side of the seal carrier. The elongatebody extends into the filter medium body which is advantageouslyembodied as a folded filter whose filter folds extend approximately inradial direction. The elongate body projects into a filter fold whosefold walls are contacting the outer side of the elongate body; thefilter fold is expanded by the elongate body. In case of an arrangementof the seal carrier surrounding the filter medium body, the positioningelement which is embodied as an elongate body extends from the radialouter side of the filter medium body in radial direction inwardly.

The extension of the elongate body in radial direction for a non-roundcross section shape of the filter element amounts to, as an example, 5%to 50% of the total length, measured transverse to the longitudinal axisof the filter element, and, for example, 10% to 30% of the total width,also measured transverse to the longitudinal axis as well as viewedorthogonally to the total length. In an embodiment of the filter mediumbody as a folded filter, the radial extension of the elongate bodyadvantageously amounts to 30% to 90% of the radial length of the filterfolds. The width of the positioning element, in relation orthogonal toits length extension, is 2 mm to 15 mm, for example.

According to a further advantageous embodiment, at a wall side of thefilter medium body, preferably at the outer side of the filter mediumbody, a support grid is arranged wherein the seal carrier is supportedby the support grid. According to an expedient embodiment, seal carrierand support grid are of a one-piece configuration. In case of flowthrough the filter medium body in radial direction from the interior tothe exterior, the support grid as well as the annularly surrounding sealcarrier contact the radial outer side of the filter medium body.According to a further advantageous embodiment, the seal carrier isarranged with axial spacing relative to the nearest end face of theround filter element. Also, the positioning element can have an axialspacing relative to the next end face. The axial spacing between theseal carrier and the nearest end face of the round filter elementamounts to, for example, between 10% and 30% of the axial total heightof the round filter element. This spacing can be, for example, 30 mm to80 mm.

According to yet another advantageous embodiment, an end disk forflow-tight sealing of the filter medium body is provided at the nearestend face. Preferably, a cutout is provided in the end disk which isaxially aligned with the positioning element which has an axial spacingrelative to the end disk. In the mounted state, a housing-associatedcounter positioning element is projecting through the cutout. In thisway, the positioning element is preferably embodied as a bulge that isin particular radially projecting into the filter medium body. The bulgeand/or the positioning element is preferably open radially in outwarddirection and axially in the region of the nearest end disk or the enddisk nearest the sealing element. The bulge and/or the positioningelement moreover comprises a closed bottom in a region which is axiallyspaced apart from the end disk, in particular, as described before,preferably at the level of the sealing element. The bulge and/or thepositioning element moreover comprises two sidewalls that areseal-tightly connected with each other at the ends projecting into thefilter medium body and that, in turn, can be seal-tightly connected tothe end disk. The positioning element is thus preferably closed andconnected fluid-tightly with the end disk and the sealing element insuch a way that the raw side is separated from the clean side. In otherwords, it is preferred that the carrier wall, embodied as tube sectionsurrounding the filter medium body across a portion of its length, forforming the positioning element has an in particular radial, inparticular wedge-shaped recess wherein the recess, in the region of theseal-associated end of the carrier wall, is fluid-tightly closed and isembodied to be open at the oppositely positioned side.

According to yet another expedient embodiment, at least two positioningelements are distributed about the circumference at the seal carrier.The positioning elements are located, for example, at diametricallyopposed sides at the round filter element, for example, in case of anon-round cross section shape of the round filter element at theoppositely positioned narrow sides or at the rounded side.

The invention concerns also a filter device with an afore describedround filter element and with a filter housing for receiving the roundfilter element. The filter housing comprises expediently also a housingcover at whose inner side the counter positioning element can bearranged. The counter positioning element is embodied, for example, as ablade that, in the mounted state, projects into the hollow space in thepositioning element which is configured as an elongate body.

The seal carrier is located at or adjacent to an end face of the filterelement wherein the outer rim of the seal carrier advantageouslyprojects radially past the outer side of the filter medium body andadvantageously also past the outer side of a possibly existing supportgrid so that the outer rim serves for lateral support of the filterelement in the filter housing in the installed state. At or adjacent tothe oppositely positioned end face, the filter element can have one or aplurality of laterally radially projecting cams for support at this endface of the filter element in the filter housing. In axial direction,the filter element can have a tapering cross section shape wherein thefilter element has the larger cross section shape adjacent to the sealcarrier.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and expedient embodiments can be taken from thefurther claims, the figure description, and the drawings.

FIG. 1 shows in exploded illustration a filter device for gasfiltration, with a filter housing, a filter element, and a housingcover.

FIG. 2 shows in perspective view the filter element.

FIG. 3 shows the filter element, however without end face end disk, witha wedge-shaped positioning element that is projecting radially into thefilter medium body embodied as a folded filter.

FIG. 4 shows a circumferentially extending seal carrier of the filterelement with the radially oriented positioning element and a supportgrid.

FIG. 5 shows in perspective illustration a housing cover of the filterhousing with a counter positioning element at the inner side; and

FIG. 6 shows a section through the filter device in mounted state.

In the Figures, same components are provided with same referencecharacters.

DESCRIPTION OF PREFERRED EMBODIMENTS

In FIG. 1, a filter device 1 is illustrated that is used preferably forgas filtration, in particular for air filtration in the intake manifoldof an internal combustion engine. The filter device 1 comprises a filterhousing 2, which is comprised of a filter housing base 3 and a housingcover 4, and a filter element 5 that is insertable into the filterhousing base 3. The housing cover 4 closes off the receiving spaceinside the filter housing base for receiving the filter element 5.

The filter element 5 comprises a filter medium body 6 where thefiltration of the fluid to be purified is taking place. The filterelement 5 is configured as a round filter element; correspondingly, thefilter medium body 6 is also embodied as a round element that surroundsan inwardly positioned flow space 7 into which the fluid to be purifiedis introduced. The fluid is introduced axially, relative to thelongitudinal axis 8 of the filter element 5 and of the filter device 1,into the flow space 7. Subsequently, the fluid flows through the wall ofthe filter medium body 6 in radial direction from the interior to theexterior. Accordingly, the inner wall of the filter medium body 6 is theraw side and the outer wall is the clean side.

The filter element 5 and the filter medium body 6 comprise a stronglyovalized shape with two parallel extending long sides and semicircularnarrow sides. Also, the filter element 5 has a conical basic shape wherethe axially oppositely positioned end faces of the filter element 5 areof a different size and have an outer circumference of a different size.The axial end faces of the filter medium body 6 are covered by arespective end disk 9, 10 in a fluid-tight way, wherein the end disk 9at the larger end face of the filter element 5 is embodied to be openand comprises a flow opening 11 through which the raw fluid can flowinto the inwardly positioned flow space 7. The oppositely positioned enddisk 10, on the other hand, is embodied to be closed so that theinwardly positioned flow space 7 is also axially closed at this side.

At the closed end disk 10, cams 12 are integrally formed which extendradially in outward direction and are positioned at the long sidesadjacent to the narrow sides. The cams 12 which are formed as one piecetogether with the end disk 10 support the filter element 5 at the filterhousing base 3 in the mounted state. In radial direction, the cams 12preferably do not project farther than the oppositely positioned largerend disk 9.

At the outer wall of the filter medium body 6, there is a support grid13 which is in particular made of plastic material and is embodiedseparate from the end disks 9 and 10. The support grid 13 supports thefilter medium body at its outer wall in radial direction. Due to theradial flow through the filter medium body 6 from the interior to theexterior, a pressure oriented outwardly is produced in the filter mediumbody which is absorbed by the support grid 13. This ensures that thefilter medium body 6 is not deformed by the pressure of the fluidflowing through it.

Adjacent to the end disk 9 provided with the flow opening 11 forintroducing the raw fluid, there is a seal carrier 14 that carries asealing element 15. The seal carrier is embodied as an annularcircumferentially extending carrier wall that preferably is embodied asone piece together with the support grid 13. The sealing element 15 isdesigned as a sealing ring that is preferably inserted into a receivinggroove in the end face of the carrier wall 14 at the side that is facingaway from the neighboring end disk 9. The sealing element 15 is facingaway from the end disk 9 and is facing the oppositely positioned enddisk 10 and, in the mounted state, is resting against a circumferentialshoulder 16 at the inner wall of the receiving filter housing base 3.

In the housing cover 4, a lateral flow opening 19 is provided throughwhich the raw fluid can flow radially into the filter device. The flowopening 19 in the housing cover 4 corresponds with a further flowopening 20 provided in the filter housing base 3. When the housing cover4 is attached, the flow openings 19 and 20 are lying on top of eachother so that a continuous flow path for the raw fluid is formed.

As can be seen in FIG. 1 in connection with FIG. 2, the top end disk 9,which is arranged adjacent to the annular circumferentially extendingseal carrier 14, is provided in the region of the two oppositelypositioned semicircular narrow sides with a respective cutout 21. Thiscutout 21 makes it possible to axially insert a counter positioningelement 23 (FIGS. 5, 6), provided at the inner side of the housing cover4, into a correlated positioning element 22 (FIGS. 3, 4) in axialdirection, wherein the positioning element 22 is a component of thefilter element 5. The positioning element 22 is configured as awedge-shaped elongate body which is extending from the circumferentiallyextending seal carrier 14 radially in inward direction. The seal carrier14 is resting against the radial outer side of the filter medium body 6,the wedge-shape positioning element 22 projects, as can be seen in FIG.3, radially into the filter medium body 6 which is designed as a foldedfilter with a plurality of filter folds.

The wedge-shaped positioning element 22 is configured as a hollow bodywhile the counter positioning element 23 provided at the inner side ofthe housing cover 4 is embodied as a blade. In the mounted state, theblade 23 projects into the hollow body 22 so that centering of thefilter element 5 in the filter housing 2 is achieved. Due to thesymmetrical configuration of the filter element 5 with cutouts 21 aswell as a respective positioning element 22 in the region ofdiametrically oppositely positioned semicircular narrow sides, thefilter element 5 can be inserted into the filter housing 2 in twodifferent positions displaced by 180°. In the embodiment, there is onlyone blade-shaped counter positioning element 23 at the inner side of thehousing cover 4. In principle, it is also possible to provide two suchcounter positioning elements 23 at the inner side of the housing cover 4which each are projecting through a cutout 21 into a correlatedpositioning element 22 in the filter element 5.

The circumferentially extending sealing element 15 is supported at theinwardly projecting shoulder 16 in the filter housing base 3 andprovides for a flow-tight separation of the raw side from the cleanside. In order to prevent an undesirable bypass between raw side andclean side through the positioning element 22 embodied as a hollow body,the positioning element 22 comprises a bottom 24 in the form of a bottomplate (FIG. 4) which is formed as one piece together with the sealcarrier 14 and extends at the level of the plane of the seal carrier 14radially inwardly into the inwardly positioned hollow space of thepositioning element 22. The bottom 24 closes off the inwardly positionedhollow space in the positioning element 22 so that no undesirable flowof the fluid between raw side and clean side can be generated throughthe positioning element 22.

As can be seen furthermore in FIG. 4, the positioning element 22 extendsat the inner side of the support grid 13 axially across the entireheight of the support grid. However, it can be expedient to embody thepositioning element 22 to be axially shorter wherein basically an axialheight between the bottom 24 and the top end face of the positioningelement 22 is sufficient.

The seal carrier 14 is spaced apart axially from the top end face of theend disk 9. Between the top edge of the positioning element 22 and thetop end face of the end disk 9, there is an axial spacing so that theend disk 9, as can be seen in FIGS. 1 and 2, covers the positioningelement 22 completely. Only via the cutouts 21 provided in the end disk9 there is an access to the positioning element 22 by means of which,upon attachment of the cover 4, the blade-shaped counter positioningelement 23 can be inserted into the positioning element 22.

At the inner side of the housing cover 4, there is in addition to theblade-shaped counter positioning element 23 also a flow guiding element17 that is aligned with the counter positioning element 23. The counterpositioning element 23 as well as the flow guiding element 17 areembodied to be straight and positioned in a plane. The flow guidingelement 17 has a flow-guiding function for the supplied raw air. Betweenthe counter positioning element 23 and the flow guiding element 17,there is a gap provided at the inner side of the housing cover 4 withwhich the housing cover 4 in the attached state bridges a section of theupper end disk 9 (FIG. 6).

What is claimed is:
 1. A round filter element comprising: a filtermedium body of a filter medium, the filter medium body comprising a wallconfigured to be flowed through by a fluid to be purified in a radialdirection relative to a longitudinal axis of the filter medium body,wherein the filter medium body comprises a first end face and a secondend face; a circumferentially extending seal carrier arranged at oradjacent to the first end face of the filter medium body; a sealingelement supported at the seal carrier adjacent to a radial outer side ofthe filter medium body; a positioning element extending into the filtermedium of the filter medium body and configured to engage with form fita correlated housing-associated counter positioning element of a filterhousing when the round filter element is installed in the filterhousing; wherein the seal carrier and the sealing element separateflow-tightly a raw side of the round filter element from a clean side ofthe round filter element when the round filter element is installed inthe filter housing; wherein the positioning element is an elongate bodycomprising a longitudinal axis extending in the radial direction.
 2. Theround filter element according to claim 1, wherein the positioningelement is disposed at the seal carrier.
 3. The round filter elementaccording to claim 1, wherein the positioning element extends radiallyinto the filter medium of the filter medium body.
 4. The round filterelement according to claim 1, wherein the positioning element is ahollow body comprising a hollow space.
 5. The round filter elementaccording to claim 4, wherein a bottom is provided in the hollow spaceof the hollow body and is configured to flow-tightly seal the hollowspace.
 6. The round filter element according to claim 5, wherein thebottom is positioned axially at a level where the seal carrier isaxially arranged relative to the longitudinal axis of the filter mediumbody.
 7. The round filter element according to claim 1, wherein theelongate body is wedge-shaped.
 8. The round filter element according toclaim 1, wherein the positioning element, beginning at the radial outerside of the filter medium body, extends inwardly in the radial directioninto the filter medium of the filter medium body.
 9. The round filterelement according to claim 1, further comprising a support grid disposedat a wall side of the wall of the filter medium body, wherein the sealcarrier is supported by the support grid.
 10. The round filter elementaccording to claim 9, wherein the support grid and the seal carrier areembodied together as one piece.
 11. The round filter element accordingto claim 1, wherein the filter medium body is a folded filter.
 12. Theround filter element according to claim 1, wherein the seal carrier isarranged at an axial spacing relative to first end face of the roundfilter element.
 13. The round filter element according to claim 1,wherein at least two of said positioning element are disposed at theseal carrier and distributed about a circumference of the seal carrier.14. A round filter element comprising: a filter medium body comprising awall configured to be flowed through by a fluid to be purified in aradial direction relative to a longitudinal axis of the filter mediumbody, wherein the filter medium body comprises a first end face and asecond end face; a circumferentially extending seal carrier arranged ator adjacent to the first end face of the filter medium body; a sealingelement supported at the seal carrier adjacent to a radial outer side ofthe filter medium body; a positioning element extending into the filtermedium body and configured to engage with form fit a correlatedhousing-associated counter positioning element of a filter housing whenthe round filter element is installed in the filter housing; wherein theseal carrier and the sealing element separate flow-tightly a raw side ofthe round filter element from a clean side of the round filter elementwhen the round filter element is installed in the filter housing; an enddisk arranged at the first end face of the filter medium body, whereinthe end disk comprises a cutout disposed adjacent to the positioningelement and configured to receive the counter positioning element.
 15. Afilter device comprising: a round filter element comprising: a filtermedium body comprising a wall configured to be flowed through by a fluidto be purified in a radial direction relative to a longitudinal axis ofthe filter medium body, wherein the filter medium body comprises a firstend face and a second end face; a circumferentially extending sealcarrier arranged at or adjacent to the first end face of the filtermedium body; a sealing element supported at the seal carrier adjacent toa radial outer side of the filter medium body; a positioning elementextending into the filter medium body, wherein the positioning elementis an elongate body comprising a longitudinal axis extending in theradial direction, wherein the positioning element extends radially intothe filter medium of the filter medium body; a filter housing configuredto receive the round filter element and comprising a counter positioningelement, wherein the positioning element of the round filter element isconfigured to engage with form fit the counter positioning element ofthe filter housing when the round filter element is installed in thefilter housing, wherein the seal carrier and the sealing elementseparate flow-tightly a raw side of the round filter element from aclean side of the round filter element when the round filter element isinstalled in the filter housing.
 16. The filter device according toclaim 15, wherein the filter housing comprises a housing cover, whereinthe counter positioning element is arranged at an inner side of thehousing cover.
 17. The filter device according to claim 15, wherein thecounter positioning element is a blade.